Setting device for the stroke position of a reciprocating tool

ABSTRACT

A reciprocating tool, such as a stamping or nibbling die, has an adjustment which is driven by an electric motor. An electromechanical, photoelectric, or air pressure checking device checks the stroke position of the tool and controls operation of the motor driving the adjustment. The checking device becomes operative automatically responsive to insertion of a new tool into a tool holder and, responsive to deviation of the stroke position from a nominal or preset value, controls the motor to operate the adjustment in a direction to restore the stroke position to the nominal value. When the stroke position attains the nominal value, the supply of energy to the motor, to the checking device, or to both is automatically interrupted.

United States Patent [191 Herb [ SETTING DEVICE FOR THE STROKE POSITION OF A RECIPROCATING TOOL [75] Inventor:

[73] Assignee: Firma Trumpf & Co., Ditzingen,

Germany July 1 1, 1972 Eugen Herb, Ditzingen, Germany [22] Filed:

M1211" RM-E91 79 113 [30] Foreign Application Priority Data Dec. 25, 1973 FOREIGN PATENTS OR APPLICATIONS 1,187,108 2/1965 Germany 173/2 Primary Examiner-Ernest R. Purser Attorney-John J. McGlew et a1.

[ 57 ABSTRACT A reciprocating tool, such as a stamping or nibbling die, has an adjustment which is driven by an electric motor. An electromechanical, photoelectric, or air pressure checking device checks the stroke position of the tool and controls operation of the motor driving the adjustment. The checking device becomes operative automatically responsive to insertion of a new tool into a tool holder and, responsive to deviation of the stroke position from a nominal or preset value, controls the motor to operate the adjustment in a direction to restore the stroke position to the nominal value. When the stroke position attains the nominal value, the supply of energy to the motor, to the checking device, or to both is automatically interrupted.

PATENTEI] DEC 2 51973 SHEET 1 0F 3 SETTING DEVICE FOR THE STROKE POSITION OF A RECIPROCATING TOOL FIELD AND BACKGROUND OF THE INVENTION This invention relates to a setting device for the stroke position of a reciprocating tool, particularly a stamping or nibbling die with an adjustment.

Such tools, and their stroke positions, must be set exactly with respect to the workpiece to be machined and, when one is provided, with respect to a bottom die. The length of a tool is reduced by regrinding, so that when the tool is repositioned in the tool holder, the stroke position must be again adjusted. The same holds true when an old tool is replaced by a new tool, the new tool generally being longer.

In stamping machines and nibbling machines, it is customary to designate the stamping die, or nibbling die, the bottom die and the press pad as the tool." However, as the present invention, is, on the one hand, not directed exclusively to such tools and, on the other hand, the bottom die and the press pad are of minor interest with respect to the present invention, it is to be understood that the term tool, as used hereinafter, even in nibbling machines and stamping machines, means only the nibbling die or the stamping die.

It is known practice to set the stroke position of a reciprocating tool by means of an adjustment. However, hitherto this has been effected by hand or manually, so that the setting of the stroke position depends on the reliability and skill of the setter.

SUMMARY OF THE INVENTION The objective of the present invention is to automate the setting operation of a reciprocating tool, so that the setting can be carried out in a short time and with high precision.

For the solution of this problem, in accordance with the invention, there is provided a setting device in which the adjustment, for the automatic setting of the stroke position, is connected to a checking device for the stroke position. The checking device actuates an ajustment drive in case of a deviation of the stroke position from a nominal value. The energy supplied to the checking device, to the adjustment or shifting mechanism, or to both can be disconnected or shutoff responsive to the stroke position attaining the nominal value.

The specific design of the adjustment is of secondary importance. It is merely necessary that it has a driving unit, for example, an electric motor, which adjusts the tool, its carrier, or a partconnected with the tool in a desirable manner through intermediate elements. The checking device can be designed in a similar manner.

All checking devices that are used generally for similar control actions can be used with the invention. Thus, the checking devices can be optical or magnetic, electrical, or electronic devices. In addition, pneumatic checking devices, or a combination of the mentioned devices, can also be used. The checking device must be capable of determining the deviation of the actual value from a particularly adjustable nominal value, and translating this deviation into a corresponding signal. This signal naturally must be understood by the adjustment and be transformed into a corresponding adjustment movement. If different energy media are used, corresponding transmitters must be employed for checking and for adjustment. I

During or after the insertion of the tool into the machine, the checking device is connected or activated. If there is no deviation from the nominal value, the adjustment receives no signal and there is no adjustment of the stroke position. However, if the actual value is not identical with the nominal value, the adjustment receives information until the deviation from the nominal value is reduced to zero. The adjustment is thus stopped on the basis of the termination of the control action alone.

However, since the checking device would transmit an adjusting signal, during the following operation of the tool, to the adjustment, the energy supply to the checking device, to the adjustment, or to both must be disconnected or shutoff before the first working stroke. During operation of the tool, checking of the stroke position is no longer necessary, because the wear of the tool is so minimal that a correction of the stroke position is completely superfluous. Consequently, the energy supplied to the checking device, the adjustment, or both is reconnected or made possible only when a shorter, longer, or different tool is inserted in the machine. In itself, it would already be sufficient to disconnect or shutoff the energy supplied to the adjustment alone but, in pneumatic checking devices, for example, it is advisable to shutoff simultaneously or alternately the energy supplied to the checking device in order to avoid unnecessary expense.

In a preferred embodiment of the invention, the energy supply to the checking device, to the adjustment, or to both is shutoff automatically in case of a zero deviation of the stroke position, or the checking device and the adjustment are automatically disconnected from each other. This disconnection or separation prevents the adjustment from receiving any additional signals from the checking device until the disconnection is reversed manually or by any automatic system, and the entire setting device is reactivated.

A particularly expedient embodiment of the invention, in this respect, is characterized in that the tool starts, in its mounted end position, the operation of the adjustment and the checking device, that is, with the complete insertion and locking of the tool, the checking device is started automatically and drives the adjustment automatically in case of a deviation of the stroke position, or gives the adjustment the order to do so. The operation thus is not dependent on the operator, who must start the setting of the stroke position by actuating a switch, if the automation of this part of the setting operation is eliminated.

In another embodiment of the invention, where the tool holder or tool carrier assumes a given position when a tool is exchanged, the checking device comprises a member moving with the tool and a member which is stationary relative thereto, one of these members being designed as a switch, or having a switch, and this switch interrupting the energy supply to the adjustment, the checking device or to both in case of a zero deviation of the stroke position. The entire setting operation, including starting thereof, can thus be performed fully automatically.

The above-mentionedswitch is arranged in the circuit of an electric motor of an electric adjustment, and is normally closed. In case of a zero deviation of the stroke position, it is automatically opened. If the adjustment has a hydraulic or pneumatic motor, this switch is designed as a hydraulic or pneumatic switch, and

blocks, accordingly, the supply of compressed air or of pressure medium. Naturally, a combined electrohydraulic or electro-pneumatic switch also can be used. It is also possible to effect contact-free switches by means of a magnet.

In order to avoid any misunderstanding, it should be emphasized again that the above-described switch serves to terminate the control action and has nothing to do with the shutting off or disconnection of the checking device, the adjustment, or both by an additional switch or an additional switch gear. It should be added that a third switch gear is necessary with automatic starting of the checking device, the adjustment, or both by the inserted tool, in order to shut off the automatic setting device for the stroke position after the control action is completed. This circuit can be coupled, for example, with the connection and disconnection of the working machine itself.

One member of the checking device is preferably formed by the tool or byan element operatively connected with the tool, while the other is formed by a photocell associated with a light source and a switch. As soon as the free end of the tool enters, for example, the light beam to interrupt the latter, the control action, and thus the correction of the stroke, are terminated. I

In another embodiment of the invention, one member of the checking devicecomprises a switch and the other member a switch cam, switch finger, switch magnet, etc. In this embodiment also, the tool is displaced during the period of time that the switch cam or the like actuates the switch, which latter need not necessarily be an electric switch.

In accordance with another embodiment of the invention, one member of the checking device comprises a pneumatic switch, particularly an electro-pneumatic switch,and a blast nozzle, etc., and the other member comprises a flow-controlling element. After corresponding automatic or manual switching, compressed air issues from the nozzle, for example, above or beneath the flow controlling element, so that the compressed air can escape unhindered. This results in a corresponding signal to the. adjustment, which is maintained until the flow controlling member is directly in front of the blast nozzle and thus prevents the escape of compressed air, or at least renders such escape difficult. There is a related increase of the pressure of the compressed air in the pneumatic system which, in turn, can be used to disconnect the adjustment and thus to terminate the control action.

In a setting device with the tool driven through an eccentric and an associated connecting rod, the motor of the adjustment, in accordance with another embodiment of the invention, is connected to an eccentric bush rotatably mounted in the connecting rod and receiving the eccentric. By turning the bush, the stroke is displaced in one direction or theother. In order to be able to do this with a corresponding sensitiveness, a gear, comprising a worm and a worm wheel coupled with the bush, is arranged between the eccentric bush and the adjusting motor, in accordance with another feature of the invention.

An object of the invention is to provide an automatic setting device for the stroke position of a reciprocating tool.

"Another object of the invention is to provide such a setting device controlling operation of the adjustment of the reciprocating tool.

' A further object of the invention is to provide such a setting device in which the supply of energy to a checking means, the adjustment, or both is automatically terminated when the stroke position attains a nominal value.

Another object of the invention is to provide such a setting device which is activated responsive to insertion of a tool into the machine.

For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is a somewhat schematic illustration of a first embodiment of a setting device in accordance with the invention;

FIG. 2 is a schematic representation of the essential parts of a second embodiment of the invention;

FIG. 3 is a view, similar to FIG. 1, illustrating a third embodiment of the invention;

FIG. 4 is a view, similar to FIG. 1, ofa fourth embodiment of the invention;

FIG. 5 schematically illustrates a simplified form of the first embodiment of the invention shown in FIG. 1;

FIG. 6 is a side elevation view of an adjustment for the tool; and

FIG. 7 is a sectional view taken along the line VII- VII of FIG. 6.

DESCRIPTION OF TI-IE PREFERRED EMBODIMENTS Referring first to FIG. I, a schematically illustrated tool 3, for example, a nibbling die, is inserted into the bottom end of a plunger 2 reciprocating vertically in the direction of the double arrow 1, and is retained in plunger 2 in a suitable manner which has not been illustrated but which is well known to those skilled in the art. For changing the tool, the machine, or. its plunger 2, are stopped in an exactly predetermined position. Generally, the eccentric for the plunger drive is in its upper dead center position so that plunger 2 or tool 3 thus occupy, during a change of tools, their upper end position.

By inserting tool 3 into plunger 2, a switch 4 is automatically actuated and activates the stroke positionchecking device 5 and applies voltage to adjusting motor 6 for adjusting the stroke position of the tool. If checking device 5, whose method of operation will be described hereinafter, detects a deviation of the stroke position from a desired and adjustable nominal value, adjusting motor 6 drives the driving mechanism, not shown in detail in FIG. 1, for adjusting the stroke position of plunger 2, until the difference between the nominal and actual value of the stroke position is zero. This also reduces the distance between die 3 and a bottom die, which latter has not been shown.

On die or tool 3, there is adjustably mounted a flow controlling member 7 which is provided with a nose 8 which, in FIG. 1, substantially blocks the outlet opening or discharge end 9 of a blast pipe or blast nozzle 10, resulting in substantially complete blocking of the discharge from nozzle 10.

If nose 8 is above or below outlet opening 9, compressed air can escape unhindered from blast nozzle 10. This is the case when the stroke position of tool 3 deviates from the nominal value. Motor 6 then changes the stroke position in the direction of the zero position as long as there exists a difference between the nominal and actual value and until nose 8 has reached the position shown in FIG. 1. A pressure increase thus is produced in nozzle 10, due to the blocking of discharge therefrom, and this causes an actuation of switch 11a. Actuation of switch 1 la interrupts the energy supply to adjusting motor 6, on the one hand, and to checking device 5, on the other hand. Such interruption is maintained, even if tool 3, and thus also nose 8, are subsequently displaced upwardly or downwardly.

Compressed air is produced by a pump 12 driven by an electric motor 13 connected by lines 14 to a switch cabinet 15 which contains the entire control, particularly also a programming device for the machine tool, which has not been shown, as well as all elements belonging to the setting device, and which are not illustrated in detail. Lines 16 connect switch 11 to switch cabinet 15, and switch 4 is connected to the switch cabinet by lines 17. The connections between switch cabinet 15 and motor 6 are indicated at 18, and an electric potential is applied to the control elements in switch cabinet 15 through the terminals 19.

Flow control member 7 is secured adjustably on tool 3, as mentioned above. In a manner not shown, it has several noses at varying spacings from its bottom edge, and which can be brought into operating position, as required. It is also possible to invert flow control member 7 in order to attain a different vertical position of nose 8 relative to tool 3. In this way, it is possible that nose 8 always has about the same distance from the free end or working surface of the die.

When this end surface is reground, the length of the die changes. With minimum longitudinal variations, a correction of the nose position is not necessary, but the flow control member 7 must be changed in its position relative to too] 3 if the latter has been shortened by an excessive amount by regrinding. The same holds true in a similar manner for the insertion of a different too] with a greater or smaller length.

After working with a machine provided with plunger 2, and subsequent change of tools, the entire setting device is activated again, either automatically by switch cabinet 15, or manually, so that the entire process of checking and, if necessary adjusting the stroke position, which has previously been stopped automatically, is automatically reactivated with the insertion of a different tool.

In the variation shown in FIG. 5, pneumatic switch 11 is arranged in the circuit of motor 6 for adjustment of the stroke position. As soon as nose 8 closes the discharge opening 9, and thus causes the pressure increase in the electrohydraulic switch gear, switch I 1 opens the circuit of driving motor 6 so that the latter stops and the adjustment of the stroke position is terminated. At the same time, the supply of compressed air also has stopped in a suitable manner, so the switch 11 no longer can be closed during subsequent operation of tool 3 with the resulting unblocking of discharge opening 9. Here too, the setting device must be reactivated in a suitable manner after a change of tools.

In the embodiment of the invention shown in FIG. 4, switch 11 is actuated directly by a switch cam 20 moving with the plunger. This embodiment of the setting device works essentially in the same manner as the pneumatic alternative, but siwtch 11 is actuated mechanically and directly by the plunger or switch am 20, as mentioned above.

A setting device similar to the embodiment shown in FIG. 4 is illustrated schematically in FIG. 3, wherein switch 11 is actuated or opened by cam 20 when the correct stroke position is attained. However, in the embodiment of FIG. 3, there is also provided a switch 21 which may be closed or opened either manually or by a relay in switch cabinet 15. In addition, a self-holding relay 22 is provided, whose contacts 23 maintain the circuit of motor 6 closed even after switch 21 has been opened. As soon as switch 1 1 is opened by cam 20, selfholding relay 22 drops, so that contacts 23 are also opened and motor 6 receives no current during the working stroke of the plunger, even during subsequent closing of switch 11. This is only the case when switch 21 is again closed, so that self-holding relay 22 picks up again. Naturally, the motor starts, in this case, only when there is a deviation from the stroke position, that is, when switch 11 is closed.

FIG. 2 illustrates an embodiment of the invention in which supervision of the stroke position of tool 3 is effected by a light source 24, with a collecting lens, and a photocell 25 with a corresponding switching mechanism, which has not been shown. The method of operation again is the same. That is, as soon as beam 26 is interrupted by the bottom end 27 of toll 3, the switching mechanism associated with photocell 25 opens circuit 28 of motor 6 for adjusting the stroke position. The locking and reactivation are effected in the same manner as in the other embodiments of the invention already described.

Still referring to FIG. 2, there is arranged, on shaft 29 of adjusting motor 6, a pinion 30 meshing with a gear 31. Gear 31 is arranged between two parts 32 and 33 of plunger 2, and has two coaxial threaded pins 34 and 35, one having a right-hand thread and the other a lefthand thread. A rotation of pinion 30 thus results in an increase or decrease of the effective length of the plunger consisting of the two parts 32 and 33. The eccentric shaft is indicated at 36, while the connecting rod is indicated at 37.

Referring to FIGS. 6 and 7, an eccentric bush 39 is inserted into the bore 38 of connecting rod 37. Bush 39 is rotatably mounted and connected by a driving pin 40 to a driving gear 41 rotatably mounted on eccentric shaft 36. For this purpose, driving gear 41 has a groove 42 which extends radially and which is engaged by the free end of driving pin 40. Driving gear 41 is designed as a worm gear and is driven by a worm 43 which, in turn, is connected to motor 6 of the adjustment drive.

While specific embodiments of the invention have been shown and described in detail to illustrate theapplication of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A setting device, for automatically setting the stroke position of a reciprocating tool, such as a stamping or nibbling die, having an adjustment, said setting device comprising, in combination, driving means operating said adjustment; checking means operable to check the stroke position of the tool and controlling said driving means; means supplying energy to at least one of said checking means and said driving means; said checking means, responsive to deviation of the stroke position from a nominal value, controlling said driving means to operate said adjustment in a direction to restore the stroke position to such nominal value; and means operable to inhibit operation of said driving means.

2. A setting device, as claimed in claim 1, in which said last-named means interrupts the supply of energy to at least one of said checking means and said driving means.

3. A setting device, as claimed in claim 1, in which said last-named means is operable, responsive to the stroke position attaining such nominal value, to inhibit further operation of said driving means.

4. A setting device, as claimed in claim 1, in which said last-named means is operable, responsive to the stroke position attaining such nominal value, to interrupt the supply of energy tofat least one of said checking means and said driving means.

5. Asetting device, as claimed in claim 1, in which said last-named means is operable, responsive to the stroke position attaining such nominal value, to disconnect said checking means from said driving means.

6. A setting device, as claimed in claim 1, including means operable to insertion of a tool into a tool holder to activate said checking means.

7. A setting device, as claimed in claim I, in which a reciprocating tool holder means assumes a predetermined position when a tool is to be exchanged; said checking means comprising a member movable with the tool holder and a stationary member which is stationary relative to the tool holder; one of said members constituting a switch means interrupting the supply of energy to at least one of said checking means and said driving means responsive to the stroke position attaining such nominal value.

8. A setting device, as claimed in claim 7, in which said movable member comprises a member movable with the tool.

9. A setting device, as claimed in claim 7, in which said movable member is formed by the tool; said stationary member comprising a photocell operatively associated with a light source providing a light beam in the path of tool movement, and a switch controlled by said photocell.

10. A setting device, as claimed in claim 7, in which one of said members comprises a switch and the other of said members comprises a switch operating member.

11. A setting device, as claimed in claim 7, in which said checking means includes a pneumatic switch; one of said members comprising a blast nozzle and the other of said members comprising a flow control member operable to interrupt discharge of compressed air from said blast nozzle.

12. A setting device, as claimed in claim 1 l, in which said flow control member is mounted on the tool for vertical adjustment therealong.

13. A setting device, as claimed in claim 11, in which said flow control member has at least two spaced noses and is adjustably mounted on said tool.

14. A setting device, as claimed in claim 13, in which said noses are spaced apart in the stroke direction and said flow control member is mounted on the tool for adjustment longitudinally of the latter.

15. A setting device, as claimed in claim 13, in which said noses extend in the stroke direction and said flow control member is mounted on said tool for angular adjustment thereon.

16. A setting device, as claimed in claim 13, in which said flow control member is mounted on the tool in a manner such that it may be inverted.

17. A setting device, as claimed in claim 1, in which the tool is driven through an eccentric and an associated connecting rod; said driving means being connected to an eccentric bush rotatably mounted in the connecting rod and receiving the eccentric.

18. A setting device, as claimed in claim 17, in which said driving means comprises an electric motor; a worm rotatable by said electric motor; and a worm gear meshing with said worm and coupled with said eccentric motor. 

1. A setting device, for automatically setting the stroke position of a reciprocating tool, such as a stamping or nibbling die, having an adjustment, said setting device comprising, in combination, driving means operating said adjustment; checking means operable to check the stroke position of the tool and controlling said driving means; means supplying energy to at least one of said checking means and said driving means; said checking means, responsive to deviation of the stroke position from a nominal value, controlling said driving means to operate said adjustment in a direction to restore the stroke position to such nominal value; and means operable to inhibit operation of said driving means.
 2. A setting device, as claimed in claim 1, in which said last-named means interrupts the supply of energy to at least one of said checking means and said driving means.
 3. A setting device, as claimed in claim 1, in which said last-named means is operable, responsive to the stroke position attaining such nominal value, to inhibit further operation of said driving means.
 4. A setting device, as claimed in claim 1, in which said last-named means is operable, responsive to the stroke position attaining such nominal value, to interrupt the supply of energy to at least one of said checking means and said driving means.
 5. A setting device, as claimed in claim 1, in which said last-named means is operable, responsive to the stroke position attaining such nominal value, to disconnect said checking means from said driving means.
 6. A setting device, as claimed in claim 1, including means operable to insertion of a tool into a tool holder to activate said checking means.
 7. A setting device, as claimed in claim 1, in which a reciprocating tool holder means assumes a predetermined position when a tool is to be exchanged; said checking means comprising a member movable with the tool holder and a stationary member which is stationary relative to the tool holder; one of said members constituting a switch means interrupting the supply of energy to at least one of said checking means and said driving means responsive to the stroke position attaining such nominal value.
 8. A setting device, as claimed in claim 7, in which said movable member comprises a member movable with the tool.
 9. A setting device, as claimed in claim 7, in which said movable member is formed by the tool; said stationary member comprising a photocell operatively associated with a light source providing a light beam in the path of tool movement, and a switch controlled by said photocell.
 10. A setting device, as claimed in claim 7, in which one of said members comprises a switch and the other of said members comprises a switcH operating member.
 11. A setting device, as claimed in claim 7, in which said checking means includes a pneumatic switch; one of said members comprising a blast nozzle and the other of said members comprising a flow control member operable to interrupt discharge of compressed air from said blast nozzle.
 12. A setting device, as claimed in claim 11, in which said flow control member is mounted on the tool for vertical adjustment therealong.
 13. A setting device, as claimed in claim 11, in which said flow control member has at least two spaced noses and is adjustably mounted on said tool.
 14. A setting device, as claimed in claim 13, in which said noses are spaced apart in the stroke direction and said flow control member is mounted on the tool for adjustment longitudinally of the latter.
 15. A setting device, as claimed in claim 13, in which said noses extend in the stroke direction and said flow control member is mounted on said tool for angular adjustment thereon.
 16. A setting device, as claimed in claim 13, in which said flow control member is mounted on the tool in a manner such that it may be inverted.
 17. A setting device, as claimed in claim 1, in which the tool is driven through an eccentric and an associated connecting rod; said driving means being connected to an eccentric bush rotatably mounted in the connecting rod and receiving the eccentric.
 18. A setting device, as claimed in claim 17, in which said driving means comprises an electric motor; a worm rotatable by said electric motor; and a worm gear meshing with said worm and coupled with said eccentric motor. 